1. Field of the Invention
The present invention relates to an in-vitro method for evaluating the immunotoxicity of a test substance.
2. Description of the Related Art
Recently, the toxicity of exogenous endocrine disrupting substances such as dioxins has become a social problem. In general, the exogenous endocrine disrupting substances are also called environmental hormones. The toxicity of such environmental hormones cause a wide variety of disorders including reproductive disorders, immunological disorders, and CNS (central nervous system) disorders.
For example, it has been reported that heavy exposure to dioxins causes convulsive contraction of thymus glands in C57B1/1 mice, (Kerkvliet N. I. et al. Environmental Research 52, pp146–154 (1990)). As is described in this report, acute immunotoxicity tests for chemical substances are usually carried out in-vivo by using animals. However, such in-vivo testing is not suitable for use in screening numerous test substances quickly.
On the other hand, to detect the environmental hormonal toxicity of various substances including novel substances, the following conventional in-vitro tests are used including an E-SCREEN method, which specifically detects the estrogen action of an environmental hormone (Soto A. et al. Environ. Health Perspect, 103, pp113–122 (1995)) and a two-hybrid assay (Nishihara J. et al., Toxcol. Appl. Pharmacol. 154, pp76–83 (1999)).
In these conventional methods, the estrogen action and androgen action are detected to find reproductive toxicity.
As an in-vitro assay system for detecting immunotoxicity, an evaluation method using a human T cell line is known (A. Hossain et al. (1998), J. Biol. Chem. 273 (31), pp19853–19858). However, this method uses apoptosis as a reference and merely detects extremely limited cytotoxicity.
As described above, an in-vitro assay system for detecting the toxicity of endocrine disrupting substances other than the reproductive toxicity has not yet been established at present.